On 5/19/26 12:36 PM, Shameer Kolothum wrote:
> Command Queue Virtualization (CMDQV) is a hardware extension available
> on certain platforms that allows the SMMUv3 command queue to be
> virtualized and passed through to a VM, improving performance.
>
> For example, NVIDIA Tegra241 implements CMDQV to support virtualization
> of multiple command queues (VCMDQs).
>
> The term CMDQV is used here generically to refer to any platform that
> provides hardware support to virtualize the SMMUv3 command queue.
>
> CMDQV support is a specialization of the IOMMUFD-backed accelerated
> SMMUv3 path. Introduce an ops interface to factor out CMDQV-specific
> probe, initialization, and vIOMMU allocation logic from the base
> implementation. The ops pointer and associated state are stored in
> the accelerated SMMUv3 state.
>
> This provides an extensible design to support future vendor-specific
> CMDQV implementations.
>
> No functional change.
>
> Reviewed-by: Nicolin Chen <[email protected]>
> Signed-off-by: Shameer Kolothum <[email protected]>
> ---
> hw/arm/smmuv3-accel.h | 35 +++++++++++++++++++++++++++++++++++
> 1 file changed, 35 insertions(+)
>
> diff --git a/hw/arm/smmuv3-accel.h b/hw/arm/smmuv3-accel.h
> index 87fecb5c68..f82a7112d8 100644
> --- a/hw/arm/smmuv3-accel.h
> +++ b/hw/arm/smmuv3-accel.h
> @@ -10,11 +10,45 @@
> #define HW_ARM_SMMUV3_ACCEL_H
>
> #include "hw/arm/smmu-common.h"
> +#include "hw/arm/smmuv3.h"
> #include "system/iommufd.h"
> #ifdef CONFIG_LINUX
> #include <linux/iommufd.h>
> #endif
>
> +/*
> + * CMDQ-Virtualization (CMDQV) hardware support, extends the SMMUv3 to
> + * support multiple VCMDQs with virtualization capabilities.
> + * CMDQV specific behavior is factored behind this ops interface.
> + */
> +typedef struct SMMUv3AccelCmdqvOps {
> + /**
> + * @probe: Optional callback. Vendor-specific device probing.
> + */
> + bool (*probe)(SMMUv3State *s, HostIOMMUDeviceIOMMUFD *idev, Error
> **errp);
> + /**
> + * @init: Optional callback. Initialize CMDQV hardware.
> + */
> + bool (*init)(SMMUv3State *s, Error **errp);
> + /**
> + * @alloc_viommu: Mandatory when probe is implemented.
see my comment on 8/32. Aren't probe and alloc_viommu somehow mandatory?
Eric
> + * Allocate CMDQV viommu resources.
> + */
> + bool (*alloc_viommu)(SMMUv3State *s,
> + HostIOMMUDeviceIOMMUFD *idev,
> + uint32_t *out_viommu_id,
> + Error **errp);
> + /**
> + * @free_viommu: Optional callback. Free CMDQV viommu resources.
> + * If NULL, the viommu_id is freed directly via
> iommufd_backend_free_id().
> + */
> + void (*free_viommu)(SMMUv3State *s);
> + /**
> + * @reset: Optional callback. Reset CMDQV state.
> + */
> + void (*reset)(SMMUv3State *s);
> +} SMMUv3AccelCmdqvOps;
> +
> /*
> * Represents an accelerated SMMU instance backed by an iommufd vIOMMU
> object.
> * Holds bypass and abort proxy HWPT IDs used for device attachment.
> @@ -27,6 +61,7 @@ typedef struct SMMUv3AccelState {
> QLIST_HEAD(, SMMUv3AccelDevice) device_list;
> bool auto_mode;
> bool auto_finalised;
> + const SMMUv3AccelCmdqvOps *cmdqv_ops;
> } SMMUv3AccelState;
>
> typedef struct SMMUS1Hwpt {
